Best Practice for moving Cal/Card/Files to a new Account

Hello Nextcloud Community,

I’m re-ordering my user management. Basically I used everything as the default admin (calendar, contacts and file).
But now I’m switchin to another “format”: I split my account to different accounts for calendar, contacts and files, respectively.
The admin account should only be for managing stuff not storing actual stuff. That’s my intention.

But what is the practice for moving everything to the new account? Are there tools or settings to use?

Thanks for the help!